CHAPTER 1 INTRODUCTION 1.1 Overview The service area of wireless network is divided into cell as shown in Figure 1.1a and 1.1b. Each cell has an assigned group of discrete channels from the available bandwidth. The base station (BS) is established in each cell. Subscribers in each cell use channels assigned to each cell. Every mobile unit (MU) in the cell communicates through the BS via a channel. A region initially served by a BS in a conventional mobile system is split into several cells, each of which has its own BS; it serves by a certain number of channels. The primary rule of a BS is to terminate the radio link in the network side of the user to network interface. In a small micro cell system, a distributed channel assignment function can be implemented in BS. BSs are connected to the switching network through the wired lines. The major requirement for the future mobile communication systems is high network capacity and flexibility to accommodate time varying communication network. The limited availability of the radio frequency spectrum or bandwidth is the main reason that the future cellular mobile systems must be efficiently employed channel assignment methods to increase network capacity and adapt to time varying traffic. brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by Universiti Teknologi Malaysia Institutional Repository